1. Field of the Invention
The present invention relates to an image-signal generating apparatus for inspecting or adjusting an image-signal processing apparatus such as an endoscope video processor, etc. which performs signal processing in a solid-state image pickup device.
2. Description of the Related Art
For example, in endoscope apparatuses, television cameras having solid-state image pickup devices (collectively referred to as electronic endoscopes) are widely used, the television cameras being attached to electronic endoscopes or optical endoscopes for performing endoscopy, which are mounted with solid-state image pickup devices such as charge coupled devices (hereinafter, abbreviated as CCD), which have inserting units which are inserted into body cavities, etc.
In this case, the television cameras or the electronic endoscopes mounted with CCD are connected to endoscope video processors (or may be referred to as camera control units and hereinafter indicated as (endoscope) video processors) as image-signal processing units comprising driving systems for driving the CCD and signal processing systems for performing signal processing of generating standard image signals on the basis of output signals (which are displayed in monitors) output from the driven CCD. Further, a process of generating the standard image signals is carried out by the video processors and endoscopic images taken by the CCD are displayed in monitors.
A process of inspecting the video processors includes a substrate inspecting process in which adjustment and inspection are performed to each substrate and a body inspecting process in which inspection is performed to a combination thereof, that is, to the whole system.
Here, details of the inspection are as follows.
The inspection (adjustment) of substrates is carried out in accordance with the following flow:
(1) Adjustment of a pulse generating unit for driving the CCD;
(2) Adjustment of phase of CDS pulses;
(3) Adjustment of gains of image signals obtained from the CCD; and
(4) Other level adjustment.
In adjustment of the CCD driving pulses, since image quality depends largely upon phases, pulse widths, amplitudes thereof, it is required that they should be strictly managed. Further, in adjustment of the CDS pulses, similarly, the management of phases thereof is very important.
As shown in FIG. 24, it is required that output timings of both CDS pulse 1 SHP and CDS pulse 2 SHD for performing correlated double sampling (abbreviated as CDS) to image signals CCDout as CCD output signals output from the CCD should be adjusted.
Further, while a reset portions, etc. have angulated waveforms having small distortion as indicated by a solid line for the purpose of simplifying image signals CCDout output from the CCD in FIG. 24, the image signals in a case of inspection and adjustment in the conventional example really have rounded waveforms having large distortion as indicated by a two-dotted dash line, so that boundary portions among a reset portion, a feed-through portion, and a data portion are not exhibited clearly.
Further, in order to inspect a substrate, the inspection of image quality is carried out by taking images of various charts such as white, color bar, gray scale, etc.
In a first conventional example, the adjustment and inspection in accordance with the aforementioned (1) to (4), as shown in FIG. 25, are carried out using an inspection jig (head jig) 85 comprising a substrate 82 substantially mounted with a CCD 81, a scope cable 83 used for an endoscope (scope), and a unit 84 having a lens, an iris, and an ND filter. Then, a connector 86 at an end of the scope cable 83 is connected to a video processor to be inspected and adjusted, and then the video processor is inspected and adjusted.
In Japanese Unexamined Patent Application Publication No. 7-171096 as a second conventional example, an automatic adjustment unit for a video processor is disclosed, which outputs a test signal to a video processor by inputting a solid-state image pickup device driving signal from the video processor and automatically adjusts set values of the video processor by comparing the test signal processed by the video processor with a target value, etc.